Modern digital signal processors (DSP) face multiple challenges. Workloads continue to increase, requiring increasing bandwidth. Systems on a chip (SOC) continue to grow in size and complexity. Memory system latency severely impacts certain classes of algorithms. As transistors get smaller, memories and registers become less reliable. As software stacks get larger, the number of potential interactions and errors becomes larger. Even wires become an increasing challenge. Wide busses are difficult to route. Wire speeds continue to lag transistor speeds. Routing congestion is a continual challenge.
One technique useful for filtering functions is table look up. A data table is loaded into memory storing a set of results at a memory location corresponding to an input parameter. To perform a function, the input parameter is used to recall the pre-calculated result. This technique can be particularly valuable for seldom used and difficult to calculate mathematical functions.